Field of the Invention
The present invention relates to a method for manufacturing a high purity glycol based compound.
Description of the Related Art
In processes of manufacturing a semiconductor and a display such as a TFT-LCD, lithography is widely used to manufacture electronic circuits and pixels.
The lithography is a method that is used to generate a fine pattern on a substrate. That is, the lithography is a process of transferring a circuit pattern of a mask onto a substrate by irradiating the substrate on which photoresist that is a photosensitive material is spread with light through the mask on which a desired pattern is printed, and in respective unit processes, many kinds of chemical processing solutions, such as thinner, stripping agent, cleaning agent, and etching agent. Since a series of lithography processes as described above are mostly performed in an airtight clean zone to protect the above-described components against external pollution, regulations on formaldehyde content in the chemical processing solutions has been strengthened.
Formaldehyde is a material which stimulates a nose and eyes with a pungent odor, and has components harmful to humans and natural environments. Recently, formaldehyde has been suspected to cause cancer, and has become the center of interest all over the world. Further, legal regulations on formaldehyde have been strengthened, and it is demanded not to include formaldehyde in the chemical processing solutions.
Formaldehyde is a material having a low boiling point, and at ambient temperature, it exists in a gaseous state. However, in a glycol organic solvent having polarity, formaldehyde exists in a dissolved state.
In the case of other solvents except for the glycol organic solvent, formaldehyde can be removed through general distillation. However, in the case of the glycol organic solvent, formaldehyde is continuously generated from the glycol organic solvent due to a specific reaction, and thus it is not possible to remove formaldehyde using the general distillation.